Mounting device for flexion vibrators

ABSTRACT

A mounting device for flexion vibrators with two vibration node axes, in particular X-Y flexion quartzes in time-measuring apparatus, which have a hold on the surfaces of the flexion vibrator in the neighborhood of nodes in the points of emergence of the vibration node axes, comprising strips of approximately rectangular cross section in connection members between flexion vibrator and securing points on a support. One end of each strip respectively is directly secured to the flexion vibrator whilst the other end is connected to the support; the long sides of the sections of the strips run practically parallel to the main direction of vibration, and the strips are bent practically perpendicularly to the main direction of vibration and at least partly in a direction perpendicular to the vibration node axes.

United States Patent 72] Inventor Luc Omlin Neuchatel, Switzerland [2]] Appl. No. 888,513

[22] Filed Dec. 29, 1969 {45] Patented May 25, 1971 [73} Assignee Centre Electronique l-lorloger S. A.,

Neuchatel, Switzerland [32] Priority Jan. 13, 1969 [3 3] Switzerland [54] MOUNTING DEVICE FOR FLEXION VIBRATORS 10 Claims, 3 Drawing Figs.

[52] U.S. Cl 310/9.l, 310/94, 3 10/97 [51] Int. Cl H01v 7/00 [50] Field of Search 310/91, 9.2, 9.4, 9.7, 9.8, 8.9

[56] References Cited UNITED STATES PATENTS 3,054,915 9/1962 Houck 3 10/91 2,830,204 4/1958 Harris 310/9.1X

2,953,696 9/1960 Ruggles 310/9.l

3,206,986 9/1965 Christensen 3l0/9.1UX

2,371,613 3/1945 Fair 3l0/9.4X FORElGN PATENTS 605,288 7/1948 Great Britain 3 10/91 Primary Examiner-Milton O. Hirshfield Assistant Examiner-B. A. Reynolds Azt0rneyStevens, Davis, Miller 8!. Mosher ABSTRACT: A mounting device for flexion vibrators with two vibration node axes, in particular X-Y flexion quartzes in time-measuring apparatus, which have a hold on the surfaces of the flexion vibrator in the neighborhood of nodes in the points of emergence of the vibration node axes, comprising strips of approximately rectangular cross section in connection members between flexion vibrator and securing points on a support. One end of each strip respectively is directly secured to the flexion vibrator whilst the other end is connected to the support; the long sides of the sections of the strips run practically parallel to the mainidirection of vibration, and the strips are bent practically perpendicularly to the main direction of vibration and at least partly in a direction perpendicular to the vibration node axes.

PATENTED HAY2 5 I97] SHEET 1 [1F 2 BACKGROUND OF THE INVENTION The invention is generally concerned with a mounting device for flexion vibrators with two vibration node axes, which have a hold on the surfaces of the flexion vibrator in the neighborhood of .nodes in the points of emergence of the vibration node axes, and comprises strips of approximately rectangular section in connecting members between flcxion vibrator and securing points on a support. The invention concerns in particular a mounting device for X-Y flexion quartzes serving as regulators in time-measuring devices, primarily in portable time-measuring devices such as pocket or wristwatches.

Mounting devices for X-Y flexion quartzes for instance in portable time-measuring devices have to fulfill two conditions, the materialization of which leads to mainly contradictory constructive measures. The first condition is that under the influence of jolts or regular accelerations the flexion quartz must not come into contact with masses which might damp its vibration.'The mounting device must therefore be sufficiently stiff to prevent the quartz from knocking against other masses. The second condition is that little or no energy must be withdrawn from the flexion quartz through the mounting device, as this would lead to an irregular motion of the flexion quartz and precisely to inadmissible energy losses. According to the second condition the mounting device must therefore only cause the smallest possible forces to react on the flexion quartz in the region of its greatest motion, and must be correspondingly yielding.

Especially in the case of pocket and Wristwatches it is difficult to achieve a compromise between the two conditions in respect of their fulfillment owing to the small volume available, as on the one hand the available energy is especially small and on the other the volume is also very small.

Shock absorbers of many various kinds have already been proposed for mounting vibrating quartzes. In sizes suitable for small watches however, they require to be fashioned with great precision and in any case special space, which can only be found with difficulty in Wristwatches, for instance.

A mounting device for flexion quartzes is also already known, which is secured to the quartz in nodepoints and comprises strips of approximately rectangular section in connecting members between quartz and securing points on a support. In this case the strips form spiral springs and are wound round prolongations of the vibration node axes. This known mounting device (French Pat. Specification 980,022) has in particular the advantage that it only allows very weak torsional forces to react on the flexion quartz whilst it is vibrating. On'the other hand, however, this mounting device is obviously lacking in stiffness in the direction of the vibration node axes to such an extent that the slightest impact causes the flexion quartz to collide with the nearby support. This known device is thus unsuitable as a mounting device for flexion quartzes in small portable apparatus.

OBJECT OF THE INVENTION The object of the invention is to overcome said disadvantages, and to provide a mounting device for flexion vibrators which is relatively stiff against shocks and regular accelerations whilst it does not influence the natural vibration of the flexion vibrator. In particular this mounting device must be of very simple construction and very cheap and only take up a very little space. The immediate purpose which the invention pursues consists in providing a regulator for a small watch which is as small as possible and only consumes very little energy.

DEFINITION OF THE INVENTION According to the present invention, the above mentioned mounting device is constructed in such a manner that one end of each strip respectively is directly secured to the flexion vibrator whilst the other end is connected to the support, that the long sides of the sections of the strips run practically parallel to the main direction of vibration, and that the strips are bent practically perpendicularly to the main direction of vibration and at least partly in a direction perpendicular to the vibration node axes.

GENERAL DESCRIPTION OF THE INVENTION The strips can be bent respectively practically perpendicularly to the main direction of vibration to form loops directed towards the flexion vibrator.

In this way the reaction forces acting in particular on the flexion vibrator and which are due to the fact that during vibration the distance between the nodes constantly changes, can be kept low.

If the mounting device must be less stiff in the region of the securing points on the flexion vibrator than in the remaining regions, the components parallel to the vibration node axes of the directions in which the strips extend should be greater in the regions of the vibration node axes than the sum of all such components remaining in the regions outside the vibration node axes.

The new mounting device can, in certain circumstances, already be so stiff that its connection to the flexion vibrator becomes problematic. In this case it has been found particularly advantageous to provide the feet by which the ends of the strips are secured to the flexion vibrator with contact faces which are practically parallel to the surface of the flexion vibrator. The feet can be formed by appropriately bent over ends of the strips and the contact faces can each be formed by a part of the broad face of a strip.

According to another possibility the feet are each formed by upsetting the end of a strip and the contact faces are each formed by the end face of the same strip. During the vibration of the flexion vibrator torsional forces are set up in the strip having a rectangular cross section of each connecting member between the flexion vibrator and the securing point on the support. The torsional forces occur in particular in that part of a strip which runs practically parallel to the vibration node axis.

A strip of the mounting device according to the invention only offers a relatively slight resistance to torsion. Owing to the fact that the long sides of the cross section of a strip run approximately parallel to the principal direction of vibration, the resistance to flexion of the strip in the principal direction of vibration of the flexion vibrator is relatively high. In spite of this, periodic flexions of a strip of the described shape cannot be prevented in the mounting .device, and this even if only purely torsional forces were acting on the end of the strip which is secured to the flexion vibrator. This end thus effects a vibrating motion approximately along an arc of a circle. A virtual rotational axis runs through the center of the arc, around which, as seen from the flexion vibrator, the strip of the connecting member between the flexion vibrator and the securing point on the support is caused to swing periodically.

According to a further development of the idea of the invention, the strips are to be secured by one end to the flexion vibrator respectively in points removed from the vibration nodes from which rotational and translation forces are transmitted to the strips which cause periodic deformations within the elastic range in the strips the virtual rotational axes of which, in relation to the securing points, practically coincide with the vibration node axes so that the strips form part of the entire vibrating system. At the same time the elasticity, length and mass distribution of each strip are appropriately such that the strip is itself resonant in the range of the resonance frequency of the flexion vibrator.

In the case of a device for mounting an X-Y-flexion quartz in a pocket or wristwatch, it has been found particularly advantageous to arrange the flexion quartz in a vacuum in its own housing with the Y-Z faces parallel to the cover of the housing and secured to the same, the strips being secured on the X-Y faces of the flexion quartz on the one hand, whilst on the other they are held on pins of .insulated leads passing through the cover.-

. PREFERRED EMBODIMENT Further details of the invention will become apparent in the description of a preferred embodiment, with reference to the accompanying drawing. ln the drawing:

FIG. 1 shows a perspective view of a schematic model of a i flexion vibrator with its mounting device.

out of a crystal in a manner known per se and can be made to vibrate by piezolectric means. Other flexion vibrators of the same shape may also be made to vibrate by magnetostrictive means. The main direction of vibration of the flexion vibrator 1 is to be that of a coordinate X. The coordinates X, Y and Z, respectively X, Y and Z indicated in FIG. 1 correspond to the main directions of a crystal lattice well known in crystallography.

In FIG. 1 the essential components of a mounting device arranged according to the invention are shown to be constituted by two strips 2 and 3 which are secured by means of feet 4 and 5 to one of the X-Y faces of the flexion vibrator. The feet 4 and 5 are simply the bent over ends of the two strips 2 and 3, of each of which a part of the surface of a broad face is about parallel to the X-Y surface and is connected to the latter by soldering or welding. Torsion segments 6 and 7 of each of the two strips 2and 3 run about parallel to the vibration node axes of the flexion vibrator 1. The stresses set up in the torsion segments when the flexion vibrator 1 is vibrating are mainly torsional stresses. At the outer ends of the torsion segments the strips are bent over towards one another. The direction in which the strips are bent over is about perpendicular to the vibration node axes and to the main direction of vibration X. The parts of the strips which follow the torsion segments 6 and 7, and which run about parallel to the coordinate Y may also be called flexion segments as the forces set up in them during vibration are mainly flexion forces. In the regions of the flexion segments 8 and 9 the strips 2 and 3 are each bent to form an open loop 10 and 11 which is directed towards the flexion vibrator. Thanks to these loops the whole of the mounting device is maderesilient in the direction of the coordinate X and is able to adjust itself to the variations of the distance between the vibration node axes which occur during the vibrating motion. Theoretically the loops 10 and 11 could be bent to such an extent as to be able to act as shock absorbers coming into contact with the X-Y surfaces of the flexion vibrator 1 when the latter suffers too great a deviation owing to unusually high accelerations. Tests have shown, however, that this will certainly not be necessary in most cases.

The free ends of the strips 2 and 3 can be rigidly connected to securing points on a support.

To be complete it may be noted that a flexion vibrator is not usually held on one side only, and that connecting members similar to the visible connecting members comprising the strips 2 and 3 are secured to the invisible X-Y face of the flexion vibrator.

According to FIGS. 2 and 3, a piezolectrically driven flexion quartz 14 is arranged within a housing 13 and is held on the cover 15 of this housing by means of a mounting device arranged according to the invention. The mounting device consists of four connecting members 16, 17, 18 and 19 altogether, of which to simplify matters only the member 19 will be described in detail. Similarly to what is shown in FIG. 1 one of the Y-Z faces of the flexion quartz 14. In HO. 2 the main direction of vibration of the flexion quartz is accordingly perpendicular to the plane of the figure whilst in FIG. 3 it is in the plane of the figure and perpendicular to the coordinate Y which is not particularly indicated but corresponds to the same coordinate in HO. 1.

For instance the connecting member 19 consists essentially of a strip 20, of rectangular cross section, and of a pin 21 belonging to a glass-sealed lead in the cover 15. Soldered joints 23 and 24 connect the strip 20 on the one hand to an electrode of the flexion quartz l4 and on the other to the pin 14. The soldered joints consist essentially of silver or gold alloy.

In a practical embodiment the flexion quartz has a total length of 23.8 mm. in the Y direction, a width of 1.2 mm. in the Z direction and a thickness of 0.8 mm. in the X direction, and a resonance frequency of 8,192 Hz. The strip 20 is made of copper-beryllium bronze and its cross section has a length of 0.2 mm. and a width of 0.l mm. The total length of the connecting member 19 as well as of the other connecting members id equal to 2.6 mm. in the Y direction and the means distance between the pin 21 and the flexion quartz in the Z direction is equal to 0.7 mm. A first bend 25 at the end of the torsion segment of the strip 20 has a radius of 0.4 mm. whilst the radius of the loop 26 of the strip isequal to 0.25 mm. The summit of the loop is situated at a distance of 1.1 mm. in the Z direction from the nearest face of the flexion quartz.

The improvement afforded by the object of the application can be assembled in the case of the embodiment last described by the fact that the resulting quality factor was as high as 120,000 and that even after constant accelerations of more than 500 g. no variation of the frequency or permanent deformations could be observed. Sudden accelerations can considerably exceed l,000 g. without causing permanent damage or defective measurements. Comparative tests with flexion quartzes mounted in a similar fashion by means of connecting members of circular cross section showed that with the same quality factor at rest the resonance frequency became unsteady in the region of I00 g. and that a permanent deformation of the connecting members was to be observed. This may be principally explained by the fact that in the arrangement according to the invention the strips of rectangular cross section offer a considerable resistance to flexion in the X direction and thus prevent any excessive deviation of the flexion quartz 14 in relation to the housing 13. ln addition, the strips with a rectangular cross section offer, compared to wires with a circular cross section having the same cross-sectional surface, the advantage that their resistance to torsion is lower so that the reaction forces they exert on the flexion quartz are smaller. The described success is probably also enhanced by the fact that the securing points of the strips l6--l9 on the flexion quartz 14 are shiftedtowards the exterior in the relation to the nodal points on the X-Y faces. The previously defined virtual rotational axis of such a strip is thus brought to coincide with the vibration node axis of the flexion quartz. The virtual rotational axis as well as the vibration node axis are approximately situated in the first quarter of the loop 25. A third-component which may have led to the described success resides in the choice of the material for the strips of the connecting members 16-19. Up to now the technique in mounting devices for flexion quartzes has namely been always to use phosphor bronze, whereas beryllium bronze has now been proposed for the first time. This material is distinguished by its high elasticity and great toughness, and confers to the connecting members the properties of proper resonators, in which little energy is lost as they vibrate in the region of their own resonance frequency.

To complete the picture, it must be mentioned that the electric current is fed to the flexion quartz through the connecting members of the mounting device.

It goes without saying that the invention is not limited to time-measuring techniques.

lclaim:

l. A mounting device for flexion vibrators having at least two vibration node axes, comprising a plurality of strips being in operative engagement with said vibrator at a vibration node thereof and connected with a corresponding support means, each of said strips having a first portion, the longitudinal axis of which is generally perpendicular to the principal direction of vibration of said vibrator, a second portion, the longitudinal axis of which is substantially parallel to the longitudinal axis of said vibrator, and a third portion disposed generally perpendicularly to the axis of said vibration node, wherein the long side of said rectangular cross section lies in a plane generally parallel to the plane of said principal direction of vibration.

2. The device of claim 1, wherein said strips further comprise open loop portions disposed between said first and second portions, the plane of said loops being generally per- 4 pendicular to said principal direction of vibration.

3. Device according to claim 1, wherein said strips are secured to said vibrator by means of feet which have contact faces generally parallel to the surface of said vibrator.

3. Device according to claim 1, wherein said strips are secured to said vibrator by means of feet which have contact faces generally parallel to the surface of said vibrator. cm 4.

Device according to claim 3, wherein the feet are formed by appropriately bent over ends of the strips and that the contact faces are each formed by a part of the broad face of a strip.

5. Device according to claim 3, wherein the feet are each formed by upsetting the end of a strip, and the contact faces are each formed by the end face of the strip.

6. Device according to claim 1, wherein the strips are secured by one end to the flexion vibrator respectively in points removed from the vibration nodes from which rotational and translation forces are transmitted to the strips which cause periodic deformations within the elastic range in the strips the virtual rotational axes of which, in relation to the securing points, practically coincide with the vibration node axes, so that the strips form part of the entire vibrating system.

7. Device according to claim 6, wherein the elasticity, length and mass distribution of each strip is such that the strip itself is resonant in the range of the resonance frequency of the flexion vibrator.

8. Device according to claim 1, wherein the strips consist of beryllium bronze.

9. Device according to claim 1, for mounting piezoelectrically driven flexion quartzes the surface of which is coated with various electrode layers, wherein beryllium bronze strips are each directly connected to one of the electrode layers and form electrically conducting leads.

flexion quartz in a pocket or wristwatch, wherein the flexion quartz is arranged in a vacuum in its own housing with the Y- --Z faces parallel to the cover of the housing and secured to the same, and that the strips are secured on the X-Y faces of the flexion quartz on the one hand, whilst on the other they are held on pins of insulated leads passing through the cover.

10. Device according to claim I, for mounting an X-.Y' 

1. A mounting device for flexion vibrators having at least two vibration node axes, comprising a plurality of strips being in operative engagement with said vibrator at a vibration node thereof and connected with a corresponding support means, each of said strips having a first portion, the longitudinal axis of which is generally perpendicular to the principal direction of vibration of said vibrator, a second portion, the longitudinal axis of which is substantially parallel to the longitudinal axis of said vibrator, and a third portion disposed generally perpendicularly to the axis of said vibration node, wherein the long side of said rectangular cross section lies in a plane generally parallel to the plane of said principal direction of vibration.
 2. The device of claim 1, wherein said strips further comprise open loop portions disposed between said first and second portions, the plane of said loops being generally perpendicular to said principal direction of vibration.
 3. Device according to claim 1, wherein said strips are secured to said vibrator by means of feet which have contact faces generally parallel to the surface of said vibrator.
 3. Device according to claim 1, wherein said strips are secured to said vibrator by means of feet which have contact faces generally parallel to the surface of said vibrator. cm
 4. Device according to claim 3, wherein the feet are formed by appropriately bent over ends of the strips and that the contact faces are each formed by a part of the broad face of a strip.
 5. Device according to claim 3, wherein the feet are each formed by upsetting the end of a strip, and the contact faces are each formed by the end face of the strip.
 6. Device according to claim 1, wherein the strips are secured by one end to the flexion vibrator respectively in points removed from the vibration nodes from which rotational and translation forces are transmitted to the strips which cause periodic deformations within the elastic range in the strips the virtual rotational axes of which, in relation to the securing points, practically coincide with the vibration node axes, so that the strips form part of the entire vibrating system.
 7. Device according to claim 6, wherein the elasticiTy, length and mass distribution of each strip is such that the strip itself is resonant in the range of the resonance frequency of the flexion vibrator.
 8. Device according to claim 1, wherein the strips consist of beryllium bronze.
 9. Device according to claim 1, for mounting piezoelectrically driven flexion quartzes the surface of which is coated with various electrode layers, wherein beryllium bronze strips are each directly connected to one of the electrode layers and form electrically conducting leads.
 10. Device according to claim 1, for mounting an X-Y flexion quartz in a pocket or wristwatch, wherein the flexion quartz is arranged in a vacuum in its own housing with the Y-Z faces parallel to the cover of the housing and secured to the same, and that the strips are secured on the X-Y faces of the flexion quartz on the one hand, whilst on the other they are held on pins of insulated leads passing through the cover. 